YOU SAID:

when the cat walks on the dog into the room with the dog on the cat on the mat

INTO JAPANESE

猫が犬に乗って部屋に入り、猫がマットに乗ったとき

BACK INTO ENGLISH

When a cat enters the room on a dog and a cat on a mat

INTO JAPANESE

猫が犬に乗って部屋に入り、猫がマットに乗っているとき

BACK INTO ENGLISH

When a cat enters the room on a dog and the cat is on a mat

INTO JAPANESE

猫が犬に乗って部屋に入り、猫が畳の上にいるとき

BACK INTO ENGLISH

When a cat enters the room on a dog and the cat is on a tatami mat

INTO JAPANESE

猫が犬に乗って部屋に入り、猫が畳の上にいるとき

BACK INTO ENGLISH

When a cat enters the room on a dog and the cat is on a tatami mat